1. Field of the Invention
This invention relates to and has among its objects the provision of novel prepared fruit and vegetable products and methods for making them. Further objects of the invention will be evident from the following description wherein parts and percentages are by weight unless otherwise specified.
2. Description of the Prior Art
Many vegetables are used in preparing ready-made soups, stews, etc., and fruits and vegetables are canned or pouched for distribution to the consumer. Generally, the fruits and vegetables must be precooked prior to canning or pouching them or, in the case of vegetables, incorporating them into ready-made soups, stews, and so forth. Generally, if fruits and vegetables are frozen, they become wet, soft, and mushy when thawed in preparation for consumption.
Potatoes, for example, especially those of high-solids content, fall apart or slough-off tissue when boiled or when retorted at high temperatures and pressures. Generally, low-solids potatoes are used for boiling or steaming. However, there is a limited supply of low-solids potatoes and they are available for only a short time every year.
A number of chemical additives such as calcium salts have been used to diminish the sloughing of fruit and vegetable tissue during the cooking process. However, these additives are not consistent in the effects produced. For example, chemical additives are more effective at certain stages of maturity and ineffective at others. Furthermore, these additives are effective only in certain varieties.
Another method for strengthening fruit and vegetable tissue involves precooking the fruit or vegetable at a temperature of 71.degree. C. for a period of about 20 minutes, cooling the fruit or vegetable in water at 24.degree. C. or lower, and finish cooking the fruit or vegetable at 100.degree. C. for 30 to 50 minutes with either steam or water. The so-cooked fruit or vegetable still exhibits sloughing of tissue, has an excessive moisture content, and tends to be soft and mushy.
Fruits or vegetables that will not slough in boiling water or in steam can be prepared also by first partially dehydrating the fruit or vegetable to a moisture content of 40-50%. The partially dehydrated fruits or vegetables are frozen and can be finish-cooked when desired with mininum sloughing. The above-mentioned method has important disadvantages in that it is expensive in its overall operation and, in addition, requires an excessive amount of energy. These disadvantages greatly limit its commercial use.
Shaw et al in U.S. Pat. No. 2,983,619 (hereinafter referred to as '619), disclose a process for preparing potatoes which are non-sloughing for use in preserved food products. Potatoes are precooked for about 2 to 30 minutes at temperatures between 60.degree.-100.degree. C. but short of cooking to the state of edibility. Next, the potatoes are dried at 38.degree.-121.degree. C. such that no part of the individual potato solid has more than 68% water content, by weight, and no part of such solid has less than about 40% water, by weight. After drying, the potatoes are stored in an aqueous suspension of free starch or starchy flour to render them non-sloughing.
The process of Shaw is disadvantageous because it requires an excessive amount of energy to reduce the moisture content of the treated potatoes to a level of 40-68%. However, it was considered by those skilled in the art that such a moisture reduction was essential. Furthermore, the art-skilled person considered the presence of free starch to be necessary in preventing sloughing of a potato product prepared according to Shaw.